Busted PC!

[MARTINFISH]

I have an old PC, Pentium 1 (NEC) running Windows 98, however, it has now stopped working from Boot (since the BIOS was touched I am ashamed to say... :( ), and now on start up it Windows does not load, when asked to press F2 to enter set-up on the DOS screen it freezes... if I do not press F2, it freezes anyway. Any ideas? I have tried CTRL + Alt + Del, still nothing. Please help!!