i have put a 1GB memory in?

1.2 G is relatively small by todays standards.

Make sure that the old memory and the new have the same speed rating. If you have mixed speeds, and the system accept it, you will use the slowest speed. It the old memory is slower, then removing it can make your system faster.

Do as Peccavi proposed.
Keep in mind that the task manager don't tell you everything. There are some process that NEVER show up. 100% is what is left after those processes have taken their CPU share. It's known as "Core Process", and in the task manager, if you check "Show core process time" in the performance tab, the red line show you that time. 100% is everything ABOVE that line.

Check how many process are running and how much memory they use.
Terminate those you don't use.
If you have more than one physical drive, move the paging file to the second drive and out of the system drive. Make sure that the destination drive is well defragmented before the move. It's all the beter if you place it on an empty drive or partition and give it about 2 GB minimal size, up to about 3 GB.
By default, Windows dynamicaly manage the paging file size, making it grow and shring and causing it to become fragmented and very slow to access. This in turn, slows down your system.

Then, if you can, try to install as much memory as your motherboard can support.

If it's launching applications and opening documents that is slow, then you probably need to defragment your drive(s).
A badly fragmented drive can realy make a fast computer appears slow.

Electro
April 2011

Regarding free clean up utilities use Ccleaner via filehippo and Malwarebytes which is also on the same site The former will clean out any rubbish you have collected over time. It also has the same ability to allow you to switch off start-up programs that are running in the background (rather than going through MSCONFIG). If there are web sites you want to keep there is a page which allows you to save them. If you don't the program will delete them all along with the rubbish you have gathered. Carried this out recently on an old friends P4 PC (also with 1Gb of memory) and recovered over 2Gb of hard drive space. With the registry cleaner section of this software always save each back up in case you need it. Unlikely, as I never have but you never know.

Jimmydoo
April 2011

If it's a slow start up problem look to the start up list.

If it's general slow running use Task Manager to see which processes are eating the CPU %

Just at the moment with 2 Applications running my System Idle Process is mostly 95% or so.

Get rid of any Malware - try Spybot or some other free clean up utility.

Task Manager - Processes is the place to begin...

Peccavi
March 2011