|Bug check 0x50 usually occurs after the installation of faulty hardware or in the event of failure of installed hardware (usually related to defective RAM, be it main memory, L2 RAM cache, or video RAM).|
Another common cause is the installation of a faulty system service.
Antivirus software can also trigger this error, as can a corrupted NTFS volume.
Resolving the Problem
Resolving a faulty hardware problem: If hardware has been added to the system recently, remove it to see if the error recurs. If existing hardware has failed, remove or replace the faulty component. You should run hardware diagnostics supplied by the system manufacturer. For details on these procedures, see the owner's manual for your computer.
Resolving a faulty system service problem: Disable the service and confirm that this resolves the error. If so, contact the manufacturer of the system service about a possible update. If the error occurs during system startup, restart your computer, and press F8 at the character-mode menu that displays the operating system choices. At the resulting Windows Advanced Options menu, choose the Last Known Good Configuration option. This option is most effective when only one driver or service is added at a time.
Resolving an antivirus software problem: Disable the program and confirm that this resolves the error. If it does, contact the manufacturer of the program about a possible update.
Resolving a corrupted NTFS volume problem: Run Chkdsk /f /r to detect and repair disk errors. You must restart the system before the disk scan begins on a system partition. If the hard disk is SCSI, check for problems between the SCSI controller and the disk.
Finally, check the System Log in Event Viewer for additional error messages that might help pinpoint the device or driver that is causing the error. Disabling memory caching of the BIOS might also resolve it.
The first error on overheating might be an indication of where to look for the problem to begin with.
Keeping the systems insides clean is great but that doesn't have much to do with the cooling fans themselves from going bad. Especially the chip cooling fans. If they do not run at optimum speed then this will also cause the system to shut down. Watch the fans on start up and see if they seem sluggish or slow.
Graphics cards have a fan as well and this fan can cause the graphics cards to over heat as well. To determine an over heating issue the simplest way is to just open the dside cover and use a small house fan to blow cool air inside to see if it runs cooler and solves the problem.
You mentioned the computer being 7 years old
One other issue could be the thermal paste used between the CPU chip and the heatsink itself. .I have found that it hardens after some time and looses it's abillity to transfer heat to the heatsink and will cause overheating problems.