[Eden1]

Hi ,
First time poster and i wonder if anyone can help or recognise this problem .
Basically my previous system ( i hae since upgraded ) developed this fault but i'm hoping i can fix this one to keep as a backup .
System is an Emachines E4076
Pentium4 Processor -Windows XP Media Centre
3.06 Ghz(533 mhz FSB/2 GB RAM ( 2x1 gb) Ddr2
120 GB HDD (Seagate Barracuda 7200/ (ST3120213A )
ATI Radion Xpress 200 (+ Pci slot)

Ok i know the system is pretty old and maybe not all that but i'm just exploring the problem and if it is worthwhile attempting a repair .
Basically symptoms are it started crashing randomly back to restart - sometimes stays on for a short while but mostly crashes either during startup or soon after . I get the same thing even in safemode so not stable there either .
All 3 fans seem to be working and light on mobo is on -as is the main (blue) light on tower and smaller (orange) light below .
Main thing i have noticed is on startup all i get is this sequence -
"Emachine" logo page with " Bios F2 / Boot Menu F10"
then black page with " f11 to start recovery " in top left corner ..
black page with a click and No other writing -
then another click and then (if it makes it this far ) "Welcome/Desktop "page

Things i have tried
1 took out RAM -(restarted and heard long "beeps" from mobo
replaced each stick of RAM one at a time and restarted but each time but still have same symptoms.
2 Diskchk - check & repair function , if it makes it through all 3 parts does not stay onscreen for long enough before restarting - so not sure of errors etc .
3 repair install of Windows using manufact disk - fortunately i saved files so not bothered about losing info . I chose the "repair " option but it seems to have wiped everything off back to shop settingsetc ...but computer still crashes with same startup sequence .

My question ...can anyone recognise these symptoms and suggest a probable fault and if i do need to replace items such as HDD , PSU or even mobo (if either to blame) is it going to be (a) worth it cost wise and (b) a question of only replacing items like for like (if available) or can i upgrade the system just a bit . If the latter - perhaps you could suggest any particular makes/models etc that would be compatible with this system ?

Any help / advice appreciated ,
regards
Eden1