Cubase Studio5 Sudden ASIO overloads

I have had a scan through the forums and other posts via search engines regarding a sudden issue I am having on both new and existing projects. I run Cubase Studio 5 32bit on an i7 920 @2.6ghz, 6gig RAM, Windows 7 64bit. My interface is a (prehistoric I know) Focusrite Saffire LE.

Since about 3 weeks ago, projects I have never had an issue with (max 50% ASIO load) and new projects I have started are maxing the ASIO meter and the audio is dropping out to the point where it is unusable. I have not made any system changes or installed any new plug ins or other software and the problem just appeared from nowhere - which lead me to believe it may be some kind of virus? To that end I have run CC cleaner and malwarebytes which came up blank, and my AVG has not flagged any problems or warned of intrusions. The one change I have made (post the problems starting) is cloned my system drive over to an SSD - which has vastly improved loading/boot times etc. but do not think this has caused the problem as it was after it started as an attempt to improve things.

From reading the forum, I saw a post regarding flashing the bios which helped someone - whcih I did and updated but to no avail (Gigabyte EX58-UD3R).

I am really stumped as to why this is happening and understand it is a bit of a needle in a haystack and particular to individual systems.

I have run DPC latency checker which blanked, and also LatencyMon which tells me everything is fine. I am at a bit of a loss so was hoping somebody may have had a similar experience and there is a fix.

Plug ins I use - Stylus RMX, Omnisphere, Komplete 8 (inc Kontakt 5), and numerous fx plug ins. The only plug in I have ever had an issue with previously (putting high load on) was FX pansion Etch which I dont use because of this even though I paid good money for it.

I think I have covered everytihng but if there is any more information needed then please advise and I will do my best to answer.

I am getting very down not being able to make any music and have people waiting for pre masters which I am having to bounce everything down to stems to be able to finalise them - something I have not had to do previously and it is time consuming. Typically since it happened I have been ill and had to have surgery - which may seem like a downside - but leaves me off work for 6 to 8 weeks with plenty of time to sit and make music so extra frustration!

Any help would be very much appreciated.