I am running windows xp professional on an Hp laptop. I have got internet explorer 7 but have recently been plagued by annoying pop ups every time I go online. The worst one is C:\program files\PeDevice\tmp\tmp.html in a internet window, though it is an empty box, it seems to pop up three to four times each time. Can anyone suggest a way to get rid of it?:o

It seems that you have spyware/adware or even malware. If you're getting popups from google/msn or other trusted sites, then it is definite that you have been infected, as under normal circumstances they have no popups. If you have a sypware scanner/fixer then run an intensive scan.
If not, then the following can be used:
Windows Defender (Free for windows users)
Adaware (Free for personal use)
Spybot Search and Destroy (Also free)
Others are listed Here

Hope this helps, rate the answer