http://discussions.virtualdr.com/archive/index.php/t-195674.html<<<"First, make sure that all connections are secure, and reseat the RAM.
If no luck and it uses Windows XP, then press the F8 key during startup, select Safe mode from the menu using the arrow keys, and press Enter.
If it starts in Safe mode, then do a clean boot to find the cause:
http://support.microsoft.com/default.aspx?scid=kb;en-us;310353If it does not start in Safe mode, then restart, press the F8 key during startup, and select 'Last Known Good Configuration'.
If still no luck, then press the F2 key during startup to get into Setup(try the Del key if F2 does not work), and make sure the CD drive is configured to boot ahead of the HD.
Then, insert the Windows(or Recovery) CD, restart, and follow the steps shown here to access the Recovery Console, and do a FIXBOOT(writes a new partition table to the HD)->
http://www.webtree.ca/windowsxp/If that does not fix things, then do a FIXMBR(repairs the HD's Master Boot Record) using the same above procedure for a FIXBOOT, except substitute FIXMBR.
If still no luck, then you may have to do a repair install as described in the above link(Follow the steps for having an OEM version of XP).
If no good, then do a fresh install of XP(You will lose all data, restore points, and updates).
If there are problems doing that, then either the HD or RAM may be bad.">>>