This is my wife's machine, a Dell Inspiron 32bit Vista Home premium machine. She uses Firefox and occasionally I use explorer on it. Both are presently running like reaaaaly sllooow. In addition there is intermittent mouse lag and scrolling through lists of emails for example is very laggy. It feels like an infection, everything a bit slow, but this is really slow. I have run Malwarebites and all clear, I have run Security essentials, again, all clear. I have run a broadband speed test and performance is normal/as expected. I have uninstalled Adobe and Silverlight, both which seemed like they were recent updates, but still very slow. I keep getting a 'long running script' message come up when waiting for an internet page to load but for the most part it just hangs, and reports 'not responsive'.
I have run ccleaner, run combo fix in safe mode, and got a 'Bad pool header' message after 'Windows has detected a problem' and it nosedived into a restart.
I am now at a loss as to what to try next and feel that I need some proper help. The machine did go to the local repair shop who updated an old version of Java and sent us on our way. Needless to say that has made no difference.
This all seemed to happen very suddenly about 3 weeks ago but there were no system restore points set and so I have been unable to roll it back, hence my uninstalling of Silverlight and Adobe.
My wife has her sights on a new machine, which is fine, but I hate being beaten. Please help me if you can.