Memory upgrade, is it worth it?

I have a Fujitsu Siemens Scaleo P Desktop. It has only 1 Gig memory and i'm having trouble when rendering video and even making slideshows using Roxio Creator. The procedure slows to a stop and then fails. I've tried shutting down every othe running programme but it makes no difference. I run the ''Crucial'' scan and it tells me that to upgrade to 3Gig costs about £60. It's worth it if it works but if it's not going to make a big difference i'd rather invest in a new base unit.
Any advice please?

 

What CPU do you have? Did it just start going slow, like all of a sudden? Your machine is fairly old as comps are so I'm not sure where to go from here. BTW, I have an AMD dual core which works perfectly for trans-coding.

 

Many thank's, it tells me that my Processor is a : x86 family model 4 stepping 3, 3192 Mhz. Sorry but that doesn't mean much to me