Drive dying is my first guess, do this just in case
Basic emergency quick copy method
Most commonly used backup methods explained
10.5 huh? Botnet likely too.
https://www.zdnet.com/blog/security/mac-botnet-generated-10000-a-day-for-flashba ck-gang/11727
A fix here:
http://www.freedrweb.com/drweb+mac+light/
Surprise, Apple has left you out in the freezing cold for security updates since July 2011.
https://support.apple.com/kb/HT1222
Didn't warn you did they? Makes you all really really warm and fuzzy inside?
Hope you didn't lose much in your online banking or via credit cards etc.
Personal info in the machine? Likely all in the hands of hackers now.
Perhaps you will convey this to the Apple people in the stores when you tease them about buying a new machine?
Perhaps you won't buy a Mac ever again, perhaps you'll have media freinds that will give you free press?
Read here to harden your Mac, and your options since you on a Intel Mac, to upgrade to 10.6.3
Harden your Mac against malware attacks
Most commonly used backup methods explained