Regarding iPhoto, it sounds like your iPhoto library may have become corrupt somehow. See:
http://support.apple.com/kb/ph2512
Do the permissions repair first. If that doesn't help, try the repair option. If that doesn't work, try rebuilding.
Also, note that this problem could be due to a failing hard drive, and there's always the possibility that attempting repairs could result in further damage. Be sure you have good backups before you start. If you do not have backups, shut down your computer and do not use it again until you have at least one external hard drive for backups, then start up the machine and turn on Time Machine. Configure it to use one (or more) of the external hard drives, and allow it to complete a full backup before doing anything else.
You probably should also repair the hard drive with Disk Utility. If the repairs are unsuccessful, you have larger issues, and will probably need to replace your hard drive.
Finally, I see that you mention "issues" - emphasis on the plural - but have only mentioned one. What other issues are you experiencing?
The iPhoto issue is not related to any kind of malware or adware, so downloading anti-virus software will not fix it, and may worsen the issue, depending on the cause. I cannot say anything about any other issues before hearing what they are.