My HP computer ,windows XP is so slow when loggin on, what could be my problem, my broadband is with Talktalk?

Yeah, you might be low on disk space on the drive where your Windows swap file resides.

Try removing unneeded large files and programs to see if that speeds things up at all.

Your broadband provider is irrelevant in this situation.

not due to the broadband.

What type is your pc proccessor?

if it newer PIII, the pc is enough to open homepage.

Microsoft Registry Problems = Slow Computer!

The Windows registry, Containing information and settings for all the hardware, software, users, and preferences of your computer, whenever you make a change to the Control Panel settings, file associations, system policies, or installed software, the changes are reflected and stored in the registry.

When the Windows registry becomes very large, your computer’s can become very slow and it can cause it to be unstable.

Clean your Registry can make your computer faster

http://faster-computer-clean-registry.com/