I use the same config.. with single 2 gb module.. using W7and xp .. i m facing few graphics issue with W7... bt the computer is good enough.. i dont feel it slow.. average in W7 and super in xp
dude.. try this out. remove all pheriparals including Hard disc..do a power drain.
check the functionality of the monitor..it may be monitor issue.
try weather its completing POST with any one of the RAM module.
it could be the power issue.. remove the casing or at least replace the power unit... try to use it with constant power source.. I face same issue with my hard disc.. i jus swaped the power source.. it will surely work..
hie.. drive letter is not at a issue.. My only primary partition is named as G: ..the POST process can direct control of OS to any ONE of the drives(that can be selected using bios ). Procedure is simple and same as u do for CD and HDD option... for OS listing option you should install all the...