Call off the state of alert!
Shortly after posting this thread I noticed some processors in the task manager sucking the CPU dry! This basically caused the PC to be extremely slow whilst this processors did whatever they were doing.
On boot these files were loaded:
sms.exe
regedit.exe (no editor was in use or in the task tray!)
intranet.exe
Anyway, killing off these processors freed up the CPU and it began sailing again! (still slow dialup tho!

)
I can only assume these were put on this machine through an email virus/worm etc... I'm currently downloading the latest Norton AV 2004 software to clear this system out. This PC did have McAfee on it, but the autoupdate thing ran out last Sept!
So all is well and I got an extra ice-cream scoop for my pudding this afternoon, from my Aunty!

(I'm not really 10 years old tho! :pp)
I'll update this thread when I've virus scanned (and downloaded the 25MB trial AV software over dialup at 4KB/Sec!!!

) and report which virus/worms infected this PC.