In Taskmanager what program are using up most of the CPU.if nothing running System Idle process should be showing about 97% this is normal.If help is a bit slow coming.You could turn on Windows firewall then delete Zone alarm then run C Cleaner.If computer is running better maybe keep Windows Firewall running until you get the computer working properly.Them maybe turn Zone alarm back on or try something else. If AVG8 I have to switch my Resident Shield off as it was using a lot of the CPU up.Winaso Optimizer a good program for speeding up your computer.click here If you have downloaded SP3 lately maybe a defrag will help.
That site most probably uses a lot of pictures,so it may be you need to clean your IE temp folders,pictures can also slow down the loading time of sites so maybe turning off show pictures in IE settings help the site load faster,you could still see the picture by right clicking it and select show picture,this is not a perfect solution but it might help.
I think there is lots of garbage on ur PC...this might the cause for slowness while booting & after start up..i faced this prob in past...i tried sum software like Ace utilities , Advanced System Optimizer , PC utilities..all works f9..but i can say Advanced System Optimizer has best cleaners & optimizers in all..it has loads of utilities 4m system optimizers to uninstaller... that can speed up PC performance & can run PC smoother...right now i m using it for regular maintenance for my PC..& really helped me.It has Registry Cleaner to System Cleaner..!!This can surely helpu in speeding up PC performance.. :) It is available at Cnet.