My computer has recently started lagging loads, stupid emounts at times, it used to take about 10 seconds to start up, now takes a few minutes and cant do anything from then for another few minutes, fire fox always crashes and it can barely run sony vegas 9 anymore, my specs are : windows 7, 8gb ram, amd phenom II x6 1055t processor 2.80 ghz, 1tb internal hdd snf 1tb external hdd, cant remember graphics card but it was £100 around a year ago, everything used to work perfectly a month or 2 ago, now its slowly going down hill, ive done virus checks, always had anti virus protection ect, any tests i can run to find out whats going wrong or any tips would be great, thanks 
