For screen capture check out Evernote, it will clip screen shots you can paste into other stuff but it does way more in terms of corralling all types of stuff you may want to save for future reference. There is a free version that does most of it, for $40/year you get all the features.
Everything you save is stored on web servers the cloud, so you can share it amongst multiple computers or log in from a public machine and retrieve it. I can save a screen shot with one click, also grab a web page in it's entirety, an image or text from a web page, an email with attachments, any documents, etc. there is a windows version and a web-based version you can use one or both. There are also apps for iPhone and Android that sync with all this, you can snap a photo on your phone that syncs directly to the cloud, make a text note or even record a voice note. One click and it heads to the web and then syncs with your computer automatically.
The other great thing is you can type in keywords and it will find them in any of this information later, even text inside a PDF or in the text of a photo or screen shot. I take pictures of pages of text, and their servers OCR the text and make it searchable. It really is pretty amazing, I use it to keep just about everything I think I may want to recall at a later time.