I would suggest that you:
Determine the actual age of the hard drives installed in the current computer, as the older the drives are, the more exposure there potentially is for a hard drive failure to occur.
Determine the manufacturer's warranties on each of the hard drives - please note that warranty length can and does differ between manufacturers, as well as for different specific models of drive for any given drive manufacturer. Please also note that Sweetwater may have its own warranty that would apply to the current computer, and that may well (and almost certainly will) differ from the warranties on individual components within that computer. It would be good to know what those warranty terms are.
Evaluate your data backup process: Do you have one? It is being followed and reviewed? Does it adequately backup ALL personal data deemed required to be retained? Is the age of any existing external drive used to hold backed up data to a point where the BACKUP drive is at risk of failing? (rendering it potentially useless for recovery purposes).
Evaluate the level of technology for the current computer, to see if it makes sense to put more money in, versus buying or building a brand new computer to get more current technological advantages. IF the current computer has a lower end CPU or slower memory, it might be worth considering buying or building a new computer instead of shoring up one that may not last or might be annoyingly slow for the more demanding needs of more complex versions of Sonar. It might well be worth $50-$80 for additional memory if the rest of the computer is likely to meet the needs for performance and for reliability for the next 2-3 years, for example.
I am not trying to be any sort of doom and gloom guy - I am only suggesting you factor the above into your decision making process, so that you maximize the bang for the buck, but that you also do that wisely.
I also concur with the other posts about making sure Windows maintenance is all up to date, and I would urge you to get any hardware issues/updates/upgrades resolved prior to jumping into Windows 10. You are also going to need to make sure that whatever audio interface you are currently using will be supported in Windows 10, or you might need to factor in holding off on Windows 10 until you are in a spot to where you can pick up a newer audio interface that DOES have drivers for Win 10.
Bob Bone