Lightroom development module not working why?

[jimodonnellphotography.com]

I still use LR 5 that I purchased years ago on Amazon. It has always worked great. Suddenly yesterday I went to use it on my laptop (where I've had it for 5 years and have never once had a problem) and suddenly the develop module is disabled. It is grayed out. I cant develop. I cant export. I have no clue why. It worked just fine 3 days ago. Any ideas?

UPDATE: I uninstalled LR from my computer and then reinstalled from the CD and now it seems to be working fine...no clue what happened though. Anyway, thank you for all the help! 

[GoldingD]

Whaat is your OS/

When did you update it?

[jimodonnellphotography.com]

Windows 7. Hasnt updated for a few days. 

[AxelMatt]

Which operating system do you use?

What has been changed on your system since the error occured? Updates, Patches etc.?

Please check if your version in running in trial mode?

Do you get any error messages?

[jimodonnellphotography.com]

Windows 7

Nothing has changed.

It is not running in trial mode. It has been running just fine on my computer for several years and this change just happened yesterday. 

No error messages. 

[Per Berntsen]

Please provide some more details.

Exactly what is grayed out? The text "Develop" in the Module picker? What happens when you press D?

Or are you just seeing a gray background and no image in Develop?

And is the Export button grayed out in Library?

What happens if you press Ctrl + Shift + E? (replace Ctrl with Cmd on a Mac)

And, as requested by others, please tell us what OS you have.

[jimodonnellphotography.com]

Everything on the right side of the image is greyed out, all the development tools and options, the histogram, etc. I can see the image but it wont allow me to develop it. Nothing happens when I press D. The Export button is greyed out. Nothing happens with Ctrl + Shift + E

I am using windows 7. I dont see any recent upgrades since the last time it worked. Like I said, this worked 3 days ago then yesterday it stopped. Never seen it happen before. 

[GoldingD]

Perhaps, seen: https://www.youtube.com/watch?v=s5ROlNF3MWk

[jimodonnellphotography.com]

Thank you for this. Laura didnt have my particular issue in there.