BleepingComputer.com: Memory problems

Running a Medion MIM120, XP, with service pack 3.
When I ran a Crucial memory scan it told me there was 256 MB of memory of memory, with plenty of room to install more.
Local Drive © properties, tells me that the Total Capacity is 37.0 GB. Of this used space is 9.77 GB, free space 27.GB.
TuneUp system information tells me there is 248 MB of memory, 78℅ used.

The problem I’m having is that normally Task Manager tells me I have 37 processes running, but when I connect to the internet either with Firefox, (preferred), or with Internet Explorer, sometimes before it has even connected or shortly after it, the computer freezes and I have to open the task manager again, which will then tell me there are anything between 60 to 103 processes running, and tells me “Firefox not responding”, then it lists “Windows Task Manager running” repeatedly. I have to then shut all these processes down, including Firefox.
My ISP is BT internet and I connect wirelessly with a home hub. The connection manager tells me the speed is 48Mbps, strength excellent. Can anyone tell me if I put in more memory will this solve the problem, or is there something else I should do? As a pensioner I really can’t afford to have a professional deal with this.

I don't know how you are running XP with that little memory. If your processes jump that much just by getting online, I would suggest a virus/malware scan first. this just sounds like a malware problem. Getting any strange popups?

As far as memory, add more. I can't imagine XP with less than 512meg. Your hard drive has to be thrashing constantly using virtual memory with 256meg. I would prefer at least 1gig total memory for smooth operation.