2 of 2 people found this helpful
One might find information on the same or similar processor, AMD Athlon 64 X2 TK-53, from the above link. You can use many applications to check the processor speed, such as CPU-Z, HWMonitor, HWINFO32/64, AIDA64 and many more. Just google or bing them on the Internet and download to get a try.
In my own opinion, your processor is not burnt out, or else it would not boot up your system. 1.7GHz is its default working frequency, maybe the Cool and Quiet function make that utility to report its current speed, 800MHz, rather than your processor has some problems. If you want to upgrade to Windows 7, you'd better make sure the GPU has reached to DirectX 9C or above level, 2GB system memory for 32-bit, and 4GB system memory for 64-bit. After upgrading to Windows 7, you have billions of updates to update, that would consume lots of time and storage. Depending on the installation media, you might also need to apply some certain update packs manually to ensure the updating system working normally. My suggestion, if your GPU could reach at DirectX 10 level, and the system memory is at or above 2GB, you'd better to upgrade to Windows 10 RS1 directly.