|"boot selection failed because a required device is inaccessible"|
Vista has many things that are the same as in Windows 7.
One of the things I found out after I installed Vista is that it doesn't take kindly to programs that are not "Vista aware" changing the size of partitions that Vista made.
jefro's first link mentions that situation, for Windows 7.
If you use Vista itself to change the size of a partition Vista made - shrink or expand it - you have no problems.
"boot selection failed because a required device is inaccessible"
What's that got to do with your Topic title
"failed memory test" ??
If you tested the memory and it failed the test(s) then you have to fix that problem. If you try to install any Microsoft operating system while you're experiencing memory errors, you're very likely to have problems during Setup, or after Setup has finished, because of the memory errors having caused something to not be installed, or because of data corruption of what was installed.
The same applies when you have a problem with the optical drive reading the Windows CD or DVD properly.
You should get NO ERRORS AT ALL reading files from the CD or DVD during Setup ! If clicking on Retry or similar doesn't help, you need fix whatever is causing the problem !
When you DO get memory errors, the vast majority of the time, the ram is NOT actually "bad" - the most common causes of that are a poor connection of the ram in the ram slots, or the ram you installed is not 100% compatible with using it in your mboard, or for some ram, the settings the bios has chosen by default are not correct for your particular module(s) that you have installed.
See response 2 in this - try cleaning the contacts on the ram modules, and making sure the modules are properly seated:
For a laptop, or netbook, you must remove both its main battery and AC adapter before you do that.
For a brand name computer, see the Owner's or User's manual if you need to - how to remove or replace the ram is usually in that - it may already be in your installed programs. If you can't get into Windows, it may be on a disk that came with the computer, or you can go online and look at it or download it - it's in the downloads for your specific model.
See response 5 in this for some info about ram compatibilty, and some places where you can find out what will work in your mboard for sure:
Correction to that:
Once you know which module ID strings (part numbers) work in your mboard, you can get them from anywhere you like that has ram with those ID strings.
If you have brand name ram, it is usually easy to look up whether it's ID string is in a list of compatible modules found by using your mboard or brand name system model number.
If the ram is generic, that may be difficult or impossible.
Some ram manufacturer's modules do not strictly adhere to the JEDEC standards that most mboards bioses use to determine ram settings.
In that case, the ram settings in the bios Setup that the bios has automatically chosen may not be correct.
Check the ram settings in your bios - the ram voltage, and the ram timing numbers - those should be the same as for the specs for the modules themselves. Often the ram voltage and timing numbers are printed on the label on the modules.
If the voltage setting or timings settings in the bios are different from the specs for the ram, change them in the bios. The timing numbers must be as close as you can get to the same, or slower timings (higher numbers = slower) - you won't notice the difference the slower settings make.
If you have a mix of different modules
- don't mix ram that different voltages arespecified for - the bios will force the ram to use the lowest voltage, if "by spd" or similar is used (default settings) - ram that a higher voltage is specified for is more likely to not work properly in that situation.
- the bios settings must be those for the slowest timing settings of all the modules, or slower (higher numbers = slower).
If your ram passes a ram test, it's working fine, even if you can't determine whether it's listed for your mboard or system model anywhere.
If you do a ram test, do that AFTER having tried cleaning the contacts and making sure the ram is seated properly - otherwise any errors found may be FALSE.
If the ram is incompatible with the chipset, or on more recent computers, incompatible with the memory controller built into the cpu, it will likely FAIL a ram test - that is NOT a true indication of the ram being faulty - there is probably nothing wrong with it, and it will pass the test if installed in a mboard it is compatible with.
NOTE: Sometimes incompatible modules (or matched pairs) won't work properly when more than one is installed, but will pass when by itself.
If you want to try a memory diagnostic utility that takes a lot less time to run a full pass than memtest86 does, this one is pretty good - Microsoft's
Windows Memory Diagnostic:
It can be toggled (press T) to do a standard or a more comprehensive set of tests - use the default 6 test one first - if it passes one pass of that, use the latter one. A few of the tests in the latter set are intentionally slower.
If you don't have a floppy drive, see the Quick Start Information at that Microsoft link for how to make a bootable CD of the Windows Memory Diagnostic (you need Windiag.iso - you don't necessarily need to use the program they mention to add it to the CD).