Do they run different antivirus software, by any chance?
Do they run different versions of Word (including 32-bit or 64-bit of the same Office release)? There's always a possibility that Word has had some regressions in newer versions, and/or that one is 32-bit and the other 64-bit, and they perform much differently.
If the above is the case, and there's nothing else that looks supicious,
or that's the case, and your laptop is using 100% CPU when Word is running slow, then:
- If they are running the same release year and version (FI, 2007 Standard; but 2007 Pro for one and Standard for the other are different versions), but one 64-bit and the other 32-bit, you can install either bitness with the same key. So, you could uninstall the current Office, then install with the different bitness version. If you don't have the packaging and such handy, you can grab your key, before the uninstall, with the free
Magic Jellybean.
- If the one on your desktop is a multipack, like a Home and Student, or Home and Business, you can just remove the Office on your laptop (the key thing still applies, if you want to be able to restore it but don't have the packaging handy), and use another activation of that pack when installing on the laptop.
If they are different versions, but your laptop's is using 100% CPU when making such changes, I don't know of a free way to troubleshoot past that point. I can't seem to find Office trial versions, these days, which would be the ideal way to do it.
There's no reason for storage to affect this, really, though Word
may be updating backups (those ~$files), which is what makes me wonder about AV. However, that can be checked using the HDD activity light, Task Manager, and Resource Monitor.
Without good evidence pointing towards a RAM or HDD bottleneck, spending money in hardware will be wasted. Your 5-year-old desktop will be, at best, a 1st-gen Core i (Core -> Core 2 -> Core in-xxx -> Core in-yxxx...why, Intel, why?!), which would, again,
at best, only be slightly faster than your laptop, though is most likely a fair bit slower (we're now into the 4th gen of CPUs branded, "Core i5"). Even if the performance difference were >100% between the two, it wouldn't result in such freezing.
http://www.pcworld.com/article/224448/windows_task_manager_troubleshooting_tips.html
There's a good primer on making use of Task manager to start troubelshooting. Also check out the included Resource Monitor, if Task Manager gives nothing of note.
Now, if you can find that the disk is being accessed a lot while you're getting these freezes (have Resource Monitor and Task Manager running while you edit, then alt-tab to them and check the numbers and graphs right after such an incident), then you'd need to find the source (is it Word? Is it AV? Is it bloatware screwing with something? Is it, for whatever reason, paging in and out a lot? Etc.).
Even if hardware would end up being an easy fix, just throwing hardware at the problem is not likely to do any good.
