i've read on this forum about a sistem build around a celeron 420, a very quiet, low power usage system and having lot of spare parts i bought the cpu and a mobo and build the following configuration:
celeron 420, asus p5pl2, 2x512 ddr2 elixr, asus 7200 gs, ibm deskstar 40 gb, 7200 rpm, generic 250 w power supply.
I installed win xp sp3 and used the system for a few days and ran ok in windows, i watched some hd movies, run 3d mark 2003 and all was ok.
Then I moved the system in the livingroom and attached to the tv(hd). I used some time only for movies an net surfing but today i tried to play Nfs-MW and the game freezed every few minutes for 5-20 seconds but it didn't crash, i installed doom3 and had the same result strangely 3dmark 2003 ran ok.
It's not caused to overheating the temps are ok.
I put my power suplly,a tagan psu 450 w, but the problem persisted.
I tested the ram and the video card on my sistem and there were no problems(lol i played crysis warhead on e8200 with the 7200gs and maneged 5-10 fps).
I turned off the on-board sound but it didn't help.
The drivers and the bios are all up to date.
Only 1GB of RAM is not very much; perhaps your system's pauses are due to swapping to the hard disk. Does your hard disk LED light up when it happens? In any case, I'd install at least 2GB and better yet 3GB total RAM (if your MB has 4 RAM slots).