On Windows XP the system info reports a CPU frequency of 848 mhz. Using
cat /proc/cpuinfo gives me a CPU frequency of only 700 mhz and
lshw says that the capability is 1ghz. Is there a solution for this?
Edit: I see you're on Xubuntu. The scaling applet in XFCE4 is in the "xfce4-cpufreq-plugin" package; make sure it's installed.
Looks like that computer uses a PIII(-M?) 1GHz? That should be supported by one of the speedstep drivers in this list:
Here's a tutorial covering CPU frequency scaling in Linux.
There's a bug open on Ubuntu Jaunty that complains about CPU scaling not functioning on a similar CPU to yours. The upshot is that the kernel may be deciding that frequency scaling may not be useful for your processor. If you're running into this bug, disabling frequency scaling entirely may help you get it running faster.
If nothing else has worked yet, we'll need more information. First let's try to make sure your kernel is using the right driver for your CPU.
Please update your question with the output from these commands:
If you don't have the cpufrequtils package installed, install it ("sudo apt-get install cpufrequtils").