Mockup Blurry & Pixelated Linework

This problem has been fixed by completely removing Photoshop and reinstalling it again. 

As Bojan mentions, we'll need more information in order to provide any assistance. How are you saving/export? What settings? Can you provide screen shots of the Photoshop interface? 

Based on what can be seen in your screen shot, it looks like anti-aliasing has been disabled in your text layer. You can check this setting by selecting it in your Layers panel. Then, in the Properties panel, expand the Character section by clicking the three dots (...) in the lower right. The anti-aliasing (aa) drop-down will be right above that. You can also see the setting in the tool options bar at the top when you have the Type tool selected, between Size and the alignment options. 

The default is Sharp, so if you see something else, try changing back to this, especially if None is currently selected. 

Could you please provide more details? Can you describe the steps and format you are using to save, considering that everything else remains the same? Which app are you using to preview the saved files, and at what percentages are you viewing both files during the comparison?