The problem is I have installed win 7 on it (corporate requirement)
I doubt that this is anywhere related to your problem nor do I believe that having a lazy or understaffed IT department can be described as particularly corporate attribute. Choose another company to work for if software necrophilia in conjunction with new hardware is a problem for you.
A quick reply or help is highly appreciated.
Tell us more about the interesting and not the superfluous things. You already were on the documentation page on the HP site, that link would have been useful because you're probably looking at the wrong page or you interpret the data in the wrong way. (Which release and which kernel of "Redhat Linux"? HP has staff allocated to work on providing support for major Linux distributions internally to their users – yes I had access to that part of their Intranet – which is more like what you should be looking for than an official product support statement, unless you have a support contract with HP. In that case you should do as they say and file support request with them where you don't agree with the service, not here.) A reference to what you mean with ROS and other acronyms that may be non-unique product name should also be good practice, because I see XY problems and answers everyday.
You're asking for a pinpoint accurate technical answer, leave the whole story telling thing to marketing please.
I wanted to know how to solve these issues and also if Ubuntu is releasing a version that has all the drivers for this machine.
14.04.4 with the 15.10 kernel would be more appropriate than the older release with the 15.04 kernel regarding in kernel drivers (see: How can I upgrade the Ubuntu LTS kernel to newer?). For a laptop a model that's apparently released in 2016 you shouldn't use a kernel and related software components released in early 2015, though. A good idea is to try the development release on new hardware when it's only a few weeks away from the final release date.
If your question was about proprietary drivers than that's a bit different and I'm happy to not have to use these.
I am having problems regarding the booting of Ubuntu and graphics issues.
More details please. Screenshots, photos, logs and everything that helps to describe the exact behavior you are seeing. Please keep in mind: one problem = one question. Don't put two or more problems in one question, that makes this site less usable for everyone. Also note this site is not a bug tracker, Launchpad is.
nomodeset
to the boot parameters. – You'reAGitForNotUsingGit Apr 06 '16 at 11:50