Latency in every action

Hi all,

I'm running windows 8 on a PC (details attached), and over the past week or so, it has been lagging. Now, it doesn't lock up, the mouse doesn't become slow, and it doesn't indicate waiting. If I start Chrome, it will wait approximately 30 seconds to a minute of just doing nothing (I can do other stuff in the meantime, but that will also suffer from the same problem) before opening. When it boots, the desktop icons or taskbar icons will take time to appear.

I suspect the hard drive (SSD) - OCZ Agility 3. I've heard they're notoriously bad. PC is 2 years old now.

Any ideas?

Thanks!

Tech Support Guy System Info Utility version 1.0.0.2
OS Version: Microsoft Windows 8.1 Pro, 64 bit
Processor: Intel(R) Core(TM) i5-3570K CPU @ 3.40GHz, Intel64 Family 6 Model 58 Stepping 9
Processor Count: 4
RAM: 8142 Mb
Graphics Card: NVIDIA GeForce GTX 660 Ti, -2048 Mb
Hard Drives: C: Total - 228583 MB, Free - 75813 MB; D: Total - 953866 MB, Free - 639458 MB;
Motherboard: ASUSTeK COMPUTER INC., P8H77-I
Antivirus: Panda Cloud Antivirus, Updated and Enabled