quick help please. trying to get my computer stable

In last week i have installed edubuntu, linuxmint, xp, unbuntu. Allways the system has started to malfunction. Now my comp which is siemens brand but i think intell chip2,6gighz 1256ram, 2 satadrives about 150 gig each identical ones. Wandering if bios can have a virus ?
But basicly trouble is now that computer freezes or slows down often, and looks like it could do total crash at somepoint if i get it fixes to be stable
What i got to have on system is net connection with nokia phone which required i think a windows software… hm
anyways probaply my system would work well if i got blender,gimp and web browser and some irc messenger compination working sorry thats what i need in it,
anyways the 2 sata drives formatted to be 4 so 1 drive 75gig + 75 gig drive 2 75 gig + 75gig then get xp to be raid zero with xp or raid card software/raid card “bios”
so its writing, reading and eraseing from 2 drives at ones and fixes malfunctions.
then put some linux version also as raid.
well i dont enough of linux and xp to do this, i could just start trying but then i would loose the net connection and couldnt ask advice so any help/advice appreciated.
although with os that works from cd i could get to net.
oh and few times i caused system failure by installing stuff that shouldnt be installed, like forceing wrong display driver, well there was a reason for it

oh what a mess post i wrote

is it possible the power supply isnt enough allways?
also there is video editing card in slot which is not installed and i am not planning to install it,
maybe it causes problems?
well i maybe start trying this soon but most importantly for me, which format works for xp and linux ntsc,fat16 or fat 32 or some else

Dose windows have similar errors?
If so it may be a bad power supply or you might have a bad stick of ram
Here is a free software to do a stress test both linux and windows version available:
If you get an error when doing the stress test, pop it into google and you should find some tech support.
If the test shows that it is a ram problem, turn off the system, and remove a stick of ram, turn the system back on, and re-run the test. If you get the same error, replace the ram stick, and take out a different one and repeate untill you can run the stress test for a few hours without errors…
then just replace the bad stick of ram (you must match your other ram sticks exactly or you can cause other problems)
Generaly when computers start randomly freezing or re-starting it is the power supply.

hi Mmph
linux mint would have run fine, never if anyone has it install skype from package manager or force a display driver. Oh with the mint there was much though that cannot be done inexpensive or free that windows can do and also sort of otherwayaround
other linux disros i didnt get set up correct to work with the 2 added sata drives and i killed
the original ide drive
i´ll run the test though

oh too trouble some with cellphone net connection i think.
got to get the format figured…