Half-life 2 won't run after re-install

[pofadda]

I have HL2 installed on my Games partition and it ran after a re-installation of Win2000 on C: (I was amazed!) but just today it failed totally to run. I re-installed it over the old installation and now it wakes up Steam but hl2.exe fails to run and with no error message.

I don't really want to re-install the whole thing AGAIN and to another folder so can anyone point out what might be wrong, please?

Pofadda

 

[the show 1347]

What are your computer specs?

 

[pofadda]

Core2Duo 6400,
1 GB DDR2,
250 Spinrite HDD,
Foxconn P9657AA mobo,
Nvidia 7900GT 256MB,
SM226BW monitor.

No groovy lights or boy-racer case.

Not a hardware issue, I suspect.

Pofadda