Not a Problem, (really) Just irritating

Hi Folks, bear with me I`m new here.

I`ve an Intel P4 running fine on an ASUS P4C800=E delux, this has been fine and stable for a year or so ... (so somtimes I get it right)

I decided to upgrade my second not so important PC (well, when I say upgrade I mean I kept the screen and keyboard )
so I`ve now got an ASUS A8N-SLI-SE with Athlon 64 3700 running XP

All seems well (i`m typing from it now) however when I shut down I have to wait about 2 minutes to restart else it hangs up after hitting the two opticals and then searching for (I think) C: I`ve tried all the usuals like pulling all the usb`s etc etc. There seems very little pattern other than it ALWAYS starts fine when cold, but after only minutes of use this problem re-occurs.

As I said I can use it just fine , it`s just so irritating if I shut down having to wait to restart.

other equip
HDD Boot Maxtor 160G
HDD2 Maxtor 200G
mem 1Gb
video PCI express Nvidia GEforce 7300 GS

This is a general use and Internet PC hence the middle of the road spec.

Any Ideas would be much appreciated ...... Thanks

Anyone got any ideas, I`ve downloaded latest version 0502 of bios which is supposed to fix a boot hang up .. but it don`t (for me anyway) ....

thanks in advance

Norman