I am receiving a massage when windows restart theat "windows has detected at hard disk problem"

Tell us the make and model of your brand name system, or if you have a generic system, the make and model of your mboard. There is probably more to the message than that - what does it say after that? E.g. If it says it wants to run CHKDSK, then press no keys while that message is on the screen and let it run CHKDSK. If it says it wants to run CHKDSK every time you boot, that probably indicates you either have a poor data cable connection, a ram problem, or the hard drive is starting to fail. ...... If the computer is a desktop (or tower) computer.... It is common to un-intentionally damage IDE data cables, especially while removing them - the 80 wire ones are more likely to be damaged. What usually happens is the cable is ripped at either edge and the wires there are either damaged or severed, often right at a connector or under it's cable clamp there, where it's hard to see - if a wire is severed but it's ends are touching, the connection is intermittant, rather than being reliable. Another common thing is for the data cable to be separated from the connector contacts a bit after you have removed a cable - there should be no gap between the data cable and the connector - if there is press the cable against the connector to eliminate the gap. 80 wire data cables are also easily damaged at either edge if the cable is sharply creased at a fold in the cable. Try another data cable if in doubt. Check your SATA data cables. The connector on each end should "latch" into the socket on the drive and on the mboard, or on the drive controller card - it should not move when you merely brush your hand against it near the socket - if it does, mere vibration can cause a poor connection of it - use another SATA data cable that does "latch", or tape the connector in place. (There is a slight projection or bump on one side of the outside of the connector that "latches" it into the socket - it's easily broken off or damaged) The same thing applies for the SATA power connection. ....... Have you just changed which ram modules you have instaled? If you have, not all ram you think should be compatible will work in your mboard. If you still have the ram that was installed when the system worked fine previously, and know which module(s) it is (they are), try installing ONLY the ram that was installed previously to see if your problem then goes away. In any case.... See response 2 in this - try cleaning the contacts on the ram modules, and making sure the modules are properly seated: http://www.computing.net/hardware/w... For a laptop, you must remove both its main battery and AC adapter before you do that. See your User manual for your brand name system model, or your mboard manual, if you need to. ........ Check your hard drive with the manufacturer's diagnostics. See the latter part of response 1 in this: http://www.computing.net/windows95/... (thanks to Dan Penny for this link:) Hard Drive Diagnostics Tools and Utilities http://www.tacktech.com/display.cfm... If you don't have a floppy drive, you can get a CD image diagnostic utility from most hard drive manufacturer's web sites, but obviously you would need to make a burned CD, preferably a CD-R for best compatibilty, on another computer if you need to. If the hard drive itself tests okay, any data problems found can be fixed, one way or another.